My townhouse was built in the early 1980's, and since it was built, the state laws around which outlets are on a GFCI line have changed. The wiring itself is fine, just the receptacles need to be changed. I'm going to be placing in GFCI outlets where needed to bring it back up to code. This would require installing about half a dozen GFCI receptacles.

Unlike conventional outlets, GFCI outlets care about which wires are line (where power feeds from) and load (outlets that get power from the GFCI). Determining which is which can be tedious. My typical methodology for this has been to turn off the breaker, disconnect a NM wire, put caps on the wires that I disconnected, put the outlet back in place, and flip the breaker back on. If the outlet has power, I know that what is connected is "line", and if the outlet doesn't have power, I've found "load".

Is there an easier but still safe way to do this?

  • Do you have access to a "hot-stick" that makes some noise? Feb 22, 2015 at 5:52

1 Answer 1


Your method is safe, albeit tedious. Stick with it if the following doesn't match your comfort level.

But if you're willing to boost your risk level a bit, leave the outlet hanging on its wires outside the box and have a radio or light plugged in that indicates current without you having to touch anything. Be careful of course that the two connected wires aren't touching anything other than the outlet. For maximum safety, don't touch the outlet when it's hanging out of the box and the breaker is on. Don't do this if there are people or pets around that don't follow instructions.

If you don't have one already, a non-contact voltage detector is a good thing to have. It'll tell you quickly if a wire is hot. I like my Fluke http://www.amazon.com/Fluke-1AC-A1-II-VoltAlert-Non-Contact-Voltage/dp/B000EJ332O but there are cheaper ones at the big box stores. (Cheaper might also mean less reliable... I haven't tested that theory.) The only bad thing about these is that you'll occasionally get false positives and have to dig out your multimeter to know for sure what's going on.

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